Embedding nano-silicon in graphene nanosheets by plasma assisted milling for high capacity anode materials in lithium ion batteries

The lithium storage performance of silicon (Si) is improved substantially by forming composite of nano-Si particles embedded homogeneously in graphene nanosheets (GNs) using a simple discharge plasma assisted milling (P-milling) method. The synergistic effect of the rapid heating of the plasma and the mechanical ball mill grinding with nano-Si as nanomiller converted the graphite powder to GNs with the integration of nano-Si particles in the in-situ formed GNs. This composite structure inhibits the agglomeration of nano-Si and improves electronic conductivity. The cycling stability and rate capability are enhanced, with a stable reversible capacity of 976 mAhg−1 at 50 mAg−1 for the P-milled 20 h nano-Si/GNs composite. A full cell containing a commercial LiMn2O4 cathode is assembled and demonstrated a satisfying utilization of the P-milled nano-Si/GNs composite anode with stable working potential. This composite shows promise for application in lithium ion batteries.